qt5connectivity: fix examples compile without Qt gui module

Add upstream suggested patch to fix heartrate-server (needs only
core and bluetooth modules).

Fixes [1]:

  make[3]: Entering directory `.../build/qt5connectivity-5.9.2/examples/bluetooth'
  cd heartrate-server/ && ( test -e Makefile || .../output/host/bin/qmake -o Makefile .../build/qt5connectivity-5.9.2/examples/bluetooth/heartrate-server/heartrate-server.pro ) && /usr/bin/make -f Makefile
  Project ERROR: Unknown module(s) in QT: gui
  make[3]: *** [sub-heartrate-server-make_first] Error 3
  make[3]: Leaving directory `.../build/qt5connectivity-5.9.2/examples/bluetooth'

[1] http://autobuild.buildroot.net/results/387a21fe7fc672e5668b0afddc138cbb7197d234



Signed-off-by: Peter Seiderer <ps.report@gmx.net>
[Thomas: move patch to 5.9.2 subfolder, since it only applies to 5.9.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>